[Enhancement] Default model selection

[msenechal]

The switch currently assumes diffbot exists - but we might not want to use/configure diffbot.

It would be better if we just not arbitrarily default a model, either leave it blank at first usage (or default to 1st option in the VITE_LLM_MODELS) , and then, save the selected model as default in the session/browser storage so you don't have to re-select all the time
(and if the model in the session doesn't exist anymore, put it blank for user selection or again default to 1st option)

[kartikpersistent]

Hi @jexp what's your suggestion on this?

[jexp]

Yes agreed, I think we should only use the configured models. And then provide them in a sensible order so that the UI can select the first one.